The present invention relates to processes for the preparation of disinfected single-cell preparations and to the preparations thus prepared.
Liver transplants are the most important life-saving measure in the event of acute or chronic liver failure. In order to meet the need for transplant material, which cannot be covered by donor organs alone, methods other than complete organ transplantation have been developed in recent years, for example partial liver transplantation or the transplantation of liver cell preparations.
Single-cell preparations are of particular interest because they can be obtained from donor organs that are unsuitable for organ transplantation. In order to obtain hepatocytes from liver tissue, a two-step perfusion method is known which uses one collagenase-containing buffer and one EDTA-containing buffer (Berry and Friend, 1969, The Journal of Cell Biology, Vol. 43, pages 506-520). In said method, individual cells are enzymatically released from the tissue complex by perfusing the liver tissue with the collagenase-containing buffer.
Since the single-cell preparations obtained are medicaments, the microbial sterility must be ensured in each case. However, in approximately 70 to 80% of preparations, this is not the case since contamination usually already exists in the organ transport medium, which generally stems from the organ material or tissue material of the donor. However, with a product as valuable as human donor organs, it is desirable to obtain a large yield of transplantable tissue or cell preparations that are not microbially contaminated. Conventional decontamination processes such as heating, autoclaving, or irradiation make it impossible to maintain the viability of the cells, and, therefore, cannot be used to disinfect the tissue.
Processes for decontaminating tissue using antibiotics are likewise already known. These have been developed, for example, for storing corneal transplants (U.S. Pat. No. 4,695,536), or for decontaminating heart valve transplants (WO 92/12632 and EP 0 889 690). The exposure times to the antibiotic compositions used in said processes range from 24 hours to storage for several weeks. However, even an exposure time of 24 hours is unsuitable for highly sensitive tissue such as liver.
Furthermore, in said processes, only the surface is decontaminated. Another requirement placed on antibiotic-based decontamination processes for tissue and cells is that the process and the agents used therein should have no negative influence either on the obtaining of the liver cells or on the cell quality and viability thereof, and must be compatible with the sterility verification system used for quality control.